In general, electronic devices for a vehicle, for example, an image recording apparatus, a path guiding apparatus, an audio and video device for a vehicle, and the like are connected to an outlet (e.g., 12V power outlet) within the vehicle to be supplied with power. Among the electronic devices for the vehicle, there are devices that require a continuous supply of power and require to be operated even after an ignition of the vehicle is turned off.
In particular, a black box for a vehicle is a representative example. Since the black box for the vehicle performs a function of preparing for a traffic accident, an artificial vehicle damage accident during parking of the vehicle, or the like by recording situations while the vehicle is being driven and situations during the parking of the vehicle, the black box requires a continuous supply of power from the vehicle as long as the black box does not use a self-battery. However, since a battery for a vehicle has limited capability of about 60 AH to 100 AH, a charged battery may be fully discharged and it may be impossible for the vehicle to be driven, when a generator is not operated since the ignition of the vehicle is not turned on.
Therefore, a technology related to an apparatus for preventing an over-discharge of a battery for a vehicle which is installed between the electronic devices for the vehicle and the battery for the vehicle and prevents a power supply to the electronic devices for the vehicle when a voltage of the battery is less than a predetermined level has been proposed.